1. Field of Invention
The present disclosure relates in general to a system for draining a wellbore with an inflow control system that has a diameter that increases substantially continuously with distance away from a lower end of the wellbore.
2. Description of Prior Art
Wellbores for the production of hydrocarbon are typically lined with casing, which is then perforated adjacent a producing or formation zone. Fluid produced from the zone is typically directed to surface within production tubing that is inserted within the casing. Formation fluids generally contain stratified layers of gas, liquid hydrocarbon, and water. Boundaries between these three layers are often not highly coherent, thereby introducing difficulty for producing a designated one of the fluids. Also, the formation may have irregular properties or defaults that cause production to vary along the length of the casing. It is usually desired that the fluid flow rate remain generally consistent along the length of the casing.
A fluid flow rate from one formation that varies within the casing may inadvertently cause production from another of the formation zones. This is especially undesirable when water is present in the other formation zone, which can lead to a water breakthrough into the primary flow. To overcome this problem and to control frictional losses in wells, an inflow control device (“ICD”) is sometimes provided in the wellbore. The ICD is useful for controlling fluid flow into the wellbore and for controlling pressure drop along the wellbore. Multiple fluid flow devices may be installed, each controlling fluid flows along a section of the wellbore. These fluid control devices may be separated from each other by conventional packers. Other benefits of using fluid control devices include increasing recoverable reserves, minimizing risks of bypassing reserves, and increasing completion longevity.